The primary purpose of this project is to describe and evaluate the distribution of cancer in the United States in terms of age, sex, race, place and time in order to identify subgroups that offer possibilities for mortality reduction through intervention. Biostatistical techniques are applied to cancer morbidity and mortality rates to determine whether observed variations within and between subgroups of the population are more than fortuitous. A recent study of colorectal cancer showed that white residents of 45 countries exhibited statistically significant excess mortality rates for this disease. Incidence rates for the three countries that were within the SEER Program were significantly elevated while extent of disease and survival characteristics were only trivially different from other patients in the SEER Program, mortality reduction intervention for colorectal cancer should be based on prevention. In another study, no substantial temporal increases in pancreatic cancer incidence rates were observed during 1973-81. International comparisons of pancreatic cancer incidence rates may be biased, since autopsy rates vary appreciably between countries, and international correlations suggesting a more important role for coffee consumption than for cigarette smoking in the etiology of pancreatic cancer may not be entirely valid. A multiple primary cancer study of women with at least two nonsimultaneous breast cancers, and with the second breast cancer occuring in the contralateral breast, provided information on the association between the stage of disease for the first two primary cancers. A statistically significant, positive association was found which is consistent with an immunological hypothesis regarding the effect of cell mediated immunity associated with first breast cancer or second breast cancer behavior.